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Saturday, May 16, 2015

Two Beauties

Pleurothallis (syn. Acronia) cyanea
Two of our loveliest Pleurothallids have been flowering simultaneously on the same tree in the Tropical High Elevation House. They make quite a show together.

Pleurothallis (Acronia) calceolaris
Pleurothallis (Acronia) cyanea and P. calceolaris are allied species. Notice how similar the flowers are, apart from their color. Both have a deeply concave synsepal (in the 6 o'clock position), like a broad oval bowl. The lateral petals of the two species are similar in shape, narrowly triangular.

Now compare the dorsal sepals (in the 12 o'clock position) of the two species. The blood red flowers of P. calceolaris have a dorsal sepal that is tall and appears narrow because the margins are reflexed backwards. I like the pebbly (verrucose) texture.

P. cyanea has a dorsal sepal broadly oval in shape and wrinkled in texture. It has a lovely shimmering quality in the sunshine.

P. cyanea and P. calceolaris are both native to Colombia. We grow our plants as epiphytes on trees in the Tropical High Elevation House. We choose a shady location on the moist interior branches of a tree. When we attach an epiphytic orchid to a branch, we use a minimum amount of moss over the roots in order to encourage them to establish directly on the branch rather than in the moss. The downside of using less moss is that the plants need more frequent watering. But that's a small price to pay for increased longevity.

Sunday, April 26, 2015

Same to you, Pleurothallis linguifera

From the front, the flower of Pleurothallis (Acronialinguifera appears to be a pretty but otherwise unremarkable example of a "frog." Short column. Apical stigma. Concave dorsal sepal. But I had to laugh when I saw it in profile.

Whoever named this irreverent flower linguifera (tongue-bearing), pretty much nailed it.*  The 'tongue' is the flower's lowermost petal, or lip.

I also like the two lateral petals, which appear to be clasping.

Carlyle Luer treats this taxon as a highly variable species-complex including adonis and linguifera. The distributions of the two taxa and their intermediates overlap, making identification difficult. The plant pictured here has characteristics of both species.

Pleurothallis (Acronialinguifera complex is widely distributed through the Andes, from Colombia through Bolivia. It grows as an epiphyte or as a terrestrial at elevations as high as 3250 meters. You can see our plants flowering now in the Tropical High Elevation House, growing in one of the trees and rooted in live moss on the ground.

Among the "frogs" in our collection that I have pollinated, only this one has refused to set seed. I guess defiance is just part of its character.

*John Lindley in 1859.

Wednesday, April 22, 2015

Pleurothallis titan

What a magnificent plant. Canary yellow flowers with enormous sail like leaves. Pleurothallis (Acronia) titan is one of our most distinctive orchids and one a handful of gigantic pleurothallid species. A mature plant stands about 3' tall. You might mistake the heart shaped leaves for an Anthurium, except for the characteristic "frog" flowers appearing near the top, identifying it as a pleurothallid in the subsection (or section) Macrophyllae-Fasciculatae.

Pleurothallis titan grows as an epiphyte in cloud forests in the western cordillera of Colombia and in Panama at about 1000 to 1300 meters elevation. The species was described by Carlyle Luer in Selbyana in 1977 as Acronia titan.

Our plants flower almost continuously in the Tropical High Elevation House. You can't miss them. They do well as terrestrials in our loose soil medium of fir bark, charcoal and permatill. They also thrive as epiphytes, although their enormous size at maturity can pose problems -they need to be very firmly anchored to a tree.

A couple of plants that I cross pollinated in February are currently bearing capsules. We track and record the maturation data for every capsule we produce. When the capsule begins to split, we will sow the seeds in our lab. We plan to distribute some of the flasks and keep some of the seedlings for our collection.

Wednesday, April 15, 2015

Blue (Leaved) Orchids

Two recent additions to our orchid collection are miniatures with blue hued foliage, which makes them irresistible as far as I'm concerned.

Our Promenaea riograndensis is small enough to fit in the palm of my hand. It is a native of the cool humid mountain regions in Rio Grande Do Sul and Santa Catarina state in southern Brazil where it grows as an epiphyte, sometimes in association with P. stapeliodes, according to Jim & Barbara McQueen in Orchids of Brazil. The leaves are thin and pliable like many of the other moisture loving species in the subtribe Zygopetalinae. Since I don't have an elevation range for this species, I'm going to try growing it first in an intermediate greenhouse. If it looks stressed in summer I'll move it to the High Elevation House. The promenaeas are a fantastic group, well worth growing if you have the opportunity.

And then there's Dendrobium trantuanii, which has some of the most beautiful pseudobulbs I've seen. They are laterally flattened and a striking blue grey color. Even the stem sheaths are gorgeous. Denderobium trantuanii was described in 2003. It grows as an epiphyte in seasonally dry evergreen forests of northwestern Vietnam at 800 to 1,000 meters elevation. Our plants are growing in our warm greenhouse. In our greenhouse, they seem to prefer growing in small cedar baskets with a small amount of moss and chopped tree fern, rather than on a cork mount.

The flowers are about two centimeters across, waxy and glossy with a faint rosy blush. I'm looking forward to growing seedlings of these beauties produced in our lab.

Wednesday, April 1, 2015

A Mystery Orchid

This stopped me in my tracks. Flowering for the first time near the top a tree in the Tropical High Elevation House was an orchid I'd not noticed before. With its big solitary flower, it looked almost like an adolescent Pleurothallis gargantua. But the feeling that something was amiss sent me scurrying to the back up greenhouse for a ladder and then a closer look.

The handwritten label from Ecuagenera Nursery read 'Pleurothallis teaugei + gargantua.'  Odd. What did the plus sign mean? If Ecuagenera had created a hybrid, wouldn't they have labeled it with the names of the parents, separated by an 'x'? Is this plant a hybrid? Are teaguei and gargantua the parents?

Here's Pleurothallis gargantua, with its enormous solitary flower. For a quick guide to the floral parts, go here. The sepals look very much like those of our unknown orchid. But note that gargantua's rosy petals and yellow lip are very different.

And here's Pleurothallis teaguei flowering in the Tropical High Elevation House. If our unknown orchid is a hybrid, it could have inherited the rolled white petals from a teaguei. But where is it getting its rosy lip? Most likely not from gargantua or teaguei.

Flowering simultaneously was Pleurothallis marthae. With its rolled white petals and rosy lip, it appears to be a more likely contributor to the unknown orchid's genome.

But I can't be sure. The first step toward putting a name on this plant is to email a picture to Ecuagenera Nursery and ask for their data. Pleurothallid hybridization isn't exactly trending among commercial orchid growers, but I wouldn't be shocked if it were a hybrid. The larger Pleurothallids are fairly easy to pollinate. Alternatively, could this be a plant that Ecuagenera collected not in flower, and perhaps the names on the label were meant to be speculative? Could it be a species? There is nothing like it in Icones Pleurothallidinarum.

Whatever it is, our mystery Pleurothallis is a handsome plant. You can see it flowering now on the tree next to the door to the Conservation greenhouse.

Saturday, March 28, 2015

The Frogs

The frogs are flowering. The "frogs" are a group of related orchid species within the vast subtribe Pleurothallidinae. (Acronia section Macrophyllae-Fasciculatae or Pleurothallis subsections Acroniae and Macrophyllae-Fasciculatae, depending on who you ask). The hooded sepals and spongy lip give the flowers the whimsical appearance of open-mouthed frogs. They are awesome.
What's inside those gaping mouths? Frog flowers can be baffling if you approach them with the expectation of seeing the conventional 3 + 3 arrangement of orchid petals and sepals. Here is a close up guide to a couple of the larger species, Pleurothallis gargantua and Pleurothallis marthae.

The dorsal sepal is usually erect and often concave. The lateral sepals are fused to form a synsepal. Lying opposite each other like the two halves of a clamshell, the dorsal sepal and synsepal give the flowers their mouth-like appearance. Pleurothallis gargantua (above) is a spectacular example and the largest of the frog Pleurothallids.

Pleurothallis marthae produces flowers that seem to remain half open. In the photo above, I've pulled back the dorsal sepal so you can see the interior of the flower from above. The column is short and the stigmatic surface is at its apex, not on the underside. The tiny anther has a detachable anther cap covering a minute pair of teardrop shaped pollinia.

Above, I've cut away part of the leaf of Pleurothallis marthae so you can get a closer look at the inflorescence. The inflorescence emerges near the apex of the ramicaul, a secondary stem that looks very much like a petiole. (The actual petiole is quite short and is separated from the ramicaul by an abscission layer.) The inflorescence is subtended by a sheath, called a spathe, that mostly obscures the peduncles. From the peduncles the solitary pedicels arise, each surrounded by a clear tubular bract, and emerge from the spathe. Among frog Pleurothallids, flowers are produced singly and one at a time (as in Pleurothallis gargantua), or singly and simultaneously (as in P. marthae).

The 'frogs' in the Tropical  High Elevation House are putting on an amazing show right now. Don't miss these terrific orchids!

Saturday, March 7, 2015

Openings: Acineta cryptodonta

Here it is -the high point of my week- the long awaited opening of Acineta cryptodonta. And what a payoff. The first flowering of any unusual orchid generates some buzz among our greenhouse staff, but this plant is something special.

Maybe it's the color -the luminous pastel yellow of the flowers that keep me circling back for another look. Or the weird, almost bitter mixture of fragrances, unlike any other Euglossine-pollinated orchid that I have encountered. Is there a hint of indole in that fragrance? And the name 'cryptodonta' makes me want to open up a flower to find the hidden tooth.

It's not easy to find information about this species. Gunter Gerlach's Stanhopeinae site has some fascinating shots of the plant cloaked in moss on steep slopes in Venezuela at 1400 m. accompanied by bromeliads, aroids and gesneriads. Apparently it is also known from Colombia.

You can find our plant growing in a cedar basket in the Tropical High Elevation House growing in a mixture of moss and tree fern fiber. Be sure to look for it in the back of the greenhouse. There is a second spike forming, so if you miss it this week, check back in about three weeks.

Sunday, March 1, 2015

Dendrobium obtusiwhat?

Full disclosure: I'm not 100% certain of the name of this plant. But I'm fairly certain it is not Dendrobium obtusisepalum, the name that appeared on the label that we received from the grower.

Dendrobium obtusisepalum is a name that appears in the horticultural trade, but is not recognized as a legitimate name for any Dendrobium species. There exists a Dendrobium obtusipetalum, a synonym for Dendrobium wentianum, but that is not our plant. I believe our plant may be Dendrobium chrysopterum Schuit. & de Vogel. But I won't know until an inter-library loan delivers the original description published in the journal Orchideenfreund.

Why does it matter? In addition to maintaining the accuracy of our plant records, the correct name determines how we grow our plants. Dendrobium obtusipetalum is a high elevation species. But Dendrobium chrysopterum grows at 600 to 800 meters, with year round intermediate to warm temperatures and copious rainfall. If we want to keep this plant alive, we need to know its correct name.

Dendrobium chrysopterum grows in the Lake Kutubu area in the Southern Highlands Province of Papua New Guinea, according to Lavarack, Harris and Stocker in Dendrobium and its Relatives. It grows as an epiphyte in trees on lowland forest ridges where daytime maximum temperature reaches 87ยบ F.

Regardless of name, this plant is a stunner and it could be the most commented upon orchid we have on display this week. The candy corn colored flowers are grouped on arching leafless pseudobulbs. The new pseudobulbs have purple tinged leaves. I'm hoping we can set a capsule on this plant this week.

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